Binary and Ternary Form

The words Binary and Ternary simply mean two and three and refers to music which is in two or three distinct sections. If you hum the tune to Twinkle, twinkle little star in your head (this is called internalizing the music) you should be able to distinguish the three sections. If we were to give each section a letter, it would look like this:

A Twinkle, twinkle little star, how I wonder what you are.
B Up above the world so high, like a diamond in the sky.
A Twinkle, twinkle little star, how I wonder what you are.

So music in ternary form is can also be called ABAform, whereas binary form is simply AB! Look at the following two pieces of music and mark which form the music is in:


Form example 1Ternary or Binary?





The above example is a binary form (AB).




Form example 2Binary or Ternary?







The above example is a Ternary form  (ABA)


Using binary and ternary form is a good way of extending your compositions and giving them a good shape.

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Rondo Form

Basic Definition

Musical form where the main theme keeps recurring with contrasting sections in between (ABACADA). The A section is always in the tonic key, while the contrasting section (or episode) is in a related key. The rondo is often lively in character and is a popular final movement of a sonata, concerto, or symphony.


In rondo form, a principal theme (sometimes called the "refrain") alternates with one or more contrasting themes, generally called "episodes," but also occasionally referred to as "digressions," "couplets," or "subordinate themes." The overall form can be represented as ABACADA ... The number of themes can vary from piece to piece, and the recurring element is sometimes embellished or shortened in order to provide for variation.

The form began to be commonly used from the classical music era, though it can be found in earlier works. In the classical and romantic periods it was often used for the last movement of a sonata, symphony, concerto or piece of chamber music.

Rondo was often used by baroque composers to write Ritornello rondos. They were used in the fast movements of baroque concertos and contrast the whole orchestra (who play the main theme) against soloists (who play the episodes.) But Ritornello does differ slightly from other Rondos in that the theme is often different when it recurs but is always distinguishable as the same theme.

Classical pieces often end with a rondo. The fourth movement of a piece is often a rondo. Concertos and sonatas, however, have the third movement as a rondo.

Rondo as a character-type (as distinct from the form) equates to music that is fast and vivacious—normally allegro. Music that has been designated as "rondo" normally subscribes to both the form and character. On the other hand, there are many examples of slow and reflective works that are rondo in form but not in character. Composers such as George Gershwin normally do not identify such works as "rondo".

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Ex. of Rondo Form: Ludwig van Beethoven (1770 - 1827)
Symphony No. 3 in E flat, 'Eroica', 1st movement (Allegro con brio)